Perry Mick wrote:
I was wondering, since my engine apparently always runs lean all the
time, could that be why my oil temp is higher than everyone elses? The
excess fuel helps to cool the engine? Now that it's warm again, my oil
temps are once again too high, time to try more mods with the oil
cooler, like mod #10 or so.
--
Perry Mick
You will fool around with it the rest of your life until
you build a water manometer and find out what is really going on. :)
Do I need to fly up there with my water manometer and help out? :)
Forget the drag for a moment and cut out a rectangular hole over
the oil cooler and put some venetian blind flaps over it.
At least if that works you know you are on to something.
Paul Lamar
Been there, done that. That is what it is now, a big hole over the top
of the oil cooler. You are right, I am going to have to plumb in some
permanent pressure measuring into the oil cooler inlet and exit. But it
is still going to be trial and error to find out what works and what
doesn't. Dan's analysis awhile back showed that the ducting doesn't work
very well, I don't think any wonderful solution came out of the analysis
to fix it. I have one thing left to try, that is a block at the leading
edge of the exit duct. If that doesn't work I will probably have to add
a second oil cooler.
So what do you think of lean operation causing high oil temps?
--
Perry Mick
You need a digital camera. Last pictures I saw the outlet looked ineffective.
The heat rejected to the oil does go up a bit when lean but not
to the degree you are seeing. Your big problem is getting the
air to flow through the cooler.
I seriously doubt it has anything to do with your inlet duct.
Have you tried this configuration? It is very very important
that it looks exactly like this.
Paul Lamar
That is where I'm going next. I did have a big hole like that at the
rear of the cowl behind the oil cooler previously, but there was no exit
ducting at that time like I have now. I have to be careful not to get
the exit too close to the fan.
The best solution probably would be to use an oil cooler other than
Mazda, that has a better form factor (aspect ratio of 2:1 instead of
5:1), and locate it on the belly or elsewhere with good ducting. Has
anyone ever found a non-Mazda oil cooler that would survive?
--
Perry Mick
Custom Composite Props
mick@bridgingworlds.com
http://www.ductedfan.com
As I recall when you were using that big hole
the top skin of the strake was too close to the back side of the cooler.
The key to get air to flow through cooler is keep the exit
duct as far away from the back side of the cooler as possible.
Why not too close to the fan?
Well perhaps a square Setrabe is what
you need mounted above the water rad at the extreme back of the cowl
with the back side open to the fan. The water rad is apparently working
great and is a world record small volume size for a flying Mazda engine.
Paul Lamar
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